Acetylenically unsaturated compounds



United States Patent ACETYLENICALLY UN SATURATED COMPOUNDS Thomas E.Londergan, Niagara Falls, N. Y., assignor to E. I. du Pont de Nemoursand Company, Wilmington, Del., a corporation of Delaware ApplicationNovember 26, 1956 Serial No. 624,202

4 Claims. (Cl. 260-583) No Drawing.

This application, a continuation-in-part of my copendmg application,Serial Number'452,450, filed August 26,

1954, now abandoned, relates to acetylenieally unsatu-- rated compoundsand methods of preparing the same.

This invention has for its primary objective the provision ofl,6-diamino-2,4-hexadiynes in which the carbon atoms vicinal to theprimary amino groups are completely substituted with aliphatic radicals.The preferred object is provision of1,6-diamino-1,1,6,6-tetramethyl-2,4- hexadiyne (also known as2,7-diamino-2,7-dimethyl-3,5 octadiyne). A further object is provisionof diamino hexadiynes which on hydrogenation will yield di-primaryamines suitable as intermediates for polyamides having a high degree oflight stability. A still further object is the process for preparing thediamino-diynes of this invention in high yield from primarypropargylamines in 2,867,662 Patented Ja 6, 1959 2 hydrogenating theseprior art diynes are unsatisfactory polyamide intermediates.Di-tertiary'amines cannot be converted to polyamides and di-secondaryamines react more slowly with dicarboxylic acids than primary amines andyield low melting polyamides (Carothers, U. S. P. 2,130,948 (September20, 1938), page 2, lines 54-8), 1

The unique diynes of this invention have the structural formula:

- 2,4-hexadiyne derivatives.

A partial list of the 1,6-diamino-2,4 hexadiynes of this invention areas follows:

1,6-diamino-1 ,1 ,6,6-tetramethyl-2,4-hexadiyne1,6-diamino-1,G-dimethyl-l,6-diethyl-2,4-hexadiyne which the carbon atomvicinal to the amino group is completely substituted with normalaliphatic radicals, preferably methyl groups.

Because of their many remarkable properties, the polyamides haveattained in a relatively short time, a high place industrially. Thisindustrial importance is the result of their unique combination ofproperties, namely, high strength, good resistance to abrasion andoutstanding flex life. However, in applications involving sunlightexposure, it has not been possible to realize the full industrialpotential of the polyamides because of their deficient light stability.Applications in which this deficiency is manifest include awnings,flexible auto top decking, tentage, tobacco shade cloth, and the like.

Polyamides prepared from diamines in which the alpha carbon atoms (i. e.the carbon atoms vicinal to nitrogen atoms) are completely substitutedwith aliphatic groups show greatly improved light stability as comparedwith polyamides prepared from diamines in which these carbon atoms areunsubstituted or only partially substituted Substitution of the alphacarbonatoms of the dibasic acids used in polyamide preparation haslittle or no effect on light stability. This invention provides valuablenew intermediates for the preparation of light stable polyamides. I

It has heretofore been shown by Rose et al., British Patent 619,206(March 4, 1949) that certain diynes containing secondary and tertiaryamino groups can be produced by oxidation of secondary and tertiarypropargylamines in the presence of a cuprous catalyst. These diynes havethe structural formula:

RR'N-CHR";CEC-CEC-CHR"-NRR wherein R stands for a hydrocarbon radicaland R and R' stand for hydrocarbon radicals or hydrogen. These productsdiffer from the diamino-diynes of this invention in that they willnotfy-ield on hydrogenation di-primary amines in which the carbon atomsvicinal to the nitrogen atoms are completely substituted with aliphaticradicals. Consequently, they cannot be used as intermediates for theproduction of light stable polyamides. Furthermore, the secondary andtertiary amines obtained on l,G-diamino-l,1,6,6-tetraethyl 2,4-hexadiynel,6-diamino-1,6-dimethyl-l,6-di-n-propyl-2,4-hexadiyne1,6-diamino-1,6-diethyl-1,6 di-n-propyl-2,4-hexadiynel,6-diamino-1,1,6,6-bis(tetramethylene)-2,4-hexadiyne1,6-diamino-1,l,6,6-bis(pentamethylene)-2,4-hexadiyne It has now beenfound that primary propargylamines in which the carbon atom vicinal tothe amino group is completely substituted with aliphatic groups can bereadily converted to the 1,6-diamino-2,4-hexadiynes of this ine ventionin high'yield, namely, about of the theory or better, by exposure tooxygen in the presence of a cuprous catalyst. This is entirelyunexpected since unsubstituted proparglyamine reacts slowly and giveslow yields (viz. less than 25% of the theory) of the corresponding diynewhen subjected to the sametreatment. In the preparation ofl,6-diamino-l,1,6,6-tetramethyl-2,- 4-hexadiyhe from the correspondingdimethyl propargylamine (NH2'C(CH3)2'CECH), the reaction is exothermic,extremely rapid and involves little more than the theoretical amount ofoxygen.

The successful preparation of the substituted diaminohexadiynes of thisinvention-cannot be predicated from the prior art since primary aminogroups are more reactive than secondary or tertiary amino groups andtend to give products involving reactionof the active hydrogen atoms onnitrogen rather than the hydrogen atom on the triple bonded acetyleniccarbon atom. Such side reactions would be expected to yield al'dehydes,second ary and tertiary propargylamines, substituted hydroxylamines,hydrazides, etc. Aromatic primary and second ary amines are, forexample, readily oxidized whereas wherein R and R are n-alkyl radicalscontaining 1 to 3 carbon atoms or the RR pair is a bivalenttetramethylene or pentamethylene radical. The reaction is mostconveniently carried out in aqueous solution or slurry at somewhatelevated temperatures and ambient pressures. Around .25 -100 C. isadequate although higher temperatures and corresponding autogeneouspressures may also be used. The concentration of the compound to becoupled is not critical and may be varied up to saturation. Cuprouschloride is generally employed as the catalyst although other cuprouscompounds may be used as well.

A source'of oxygen is, of course, essential. Exposure of the reactionvessel to air at atmospheric pressure is adequate although the reactionis slow unless agitation is to be provided. Shaking the vessel orstirring it with a mechanical stirrer provides desired agitation.Alternatively, air may be bubbled through the solution to provide bothoxygen and agitation. Oxygen, itself, or any other inert gas containingfree oxygen may be substituted for air.

The invention is illustrated in detail by the following examples:

EXAMPLE 1 This example shows the preparation of 1,6-diamino-1,1,6,6-tetramethyl-2,4 hexadiyne. The equation for the reaction is:

l,1-dimethylpropargylamine (8.31 parts), water (20 parts), cuprouschloride (9.9 parts) and concentrated aqueous ammonia (20.5 parts) wereplaced in an Erlenmeyer flask connected to a source of oxygen gas. Themixture was shaken for 3 hours. In this period, oxygen equivalent to99.6% of the theoretical amount required for the coupling reaction wasabsorbed. Heat evolved by the reaction raised the temperature of themixture of 60 C. in about 10 minutes. ,The reaction mixture was filteredand the filtrate extracted continuously with ether for 18 hours. Removalof the ether from the extract yielded 7.47 parts of thediaminotetramethyl hexadiyne as reddish brown crystals. This amounts toa yield of about 91% of the theory based on either the dimethylpropargyl-amiue charged or the oxygen consumed.

The product was recrystallized for purposes of analysis from petroleumether as white needles with a melting point of 50-62.6 C.

Analysis I C I H N Calculated for CmHgNz 73. 2 9. 8 17.0 Found 73. 3 9.6 17.3

This 1,6-diamin-l,1,6,6-tetramethyl 2,4-hexadiyne was readilyhydrogenated to 1,1,6,6-tetramethyl hexamethylene .diamine in ethanolsolution at room temperature in the presence of a platinum catalyst.

EXAMPLE 2 tional 30 minutes.

tated under an atmosphere of oxygen. After one hour of the theoreticalamount of oxygen was absorbed. The reaction mixture was filtered and thefiltrate concentrated to dryness under vacuum. Hexadiyne (0.8 parts) wasobtained from the residue. This amounts to an approximately 10% oftheory yieldon propargylamine and an 11% yield based on the oxygenabsorbed.

EXAMPLES This illustrates the preparation of '1,6 diamino-2,4-hexadiyneunder somewhat different reaction conditions.

Propargylamine (13.74 par tslan'd water (250 parts containing 9 parts ofhydrogen chloride and 2.47 parts of cuprous chloride) were ,placed in aglass container under an oxygen atmosphere. Oxygen was supplied atatmospheric pressure. The reaction mixture was heated to 50-60 C. withan infrared lamp and shaken for a period of 29 hours. During this periodthe oxygen absorbed was approximately 150% of that theoreticallyrequired for the coupling reaction. The reaction mixture was filteredand the filtrate evaporated to dryness at 25-50" C. and'apressure of 3-5mm. of mercury. The residue from the evaporation was 'slurried with asolution of 30 parts of sodium hydroxide and 50 parts of water and theslurry extracted with 1000 parts of-ether. Evaporation of the ether gave3 parts of 1,6-diamino-2,4- hexadiyne as yellowish White needles. Thisis equivalent to a yield of 22% of the theoretical based onpropargylamine and 15% based on the oxygen consumption.

Recrystallization of the diamino hexadiyne for purposes of analysis gaveneedles melting at 104-105 C.

Analysis 0 H Calculated for CaHsNz .66. 7 7.5

Found 67.0 6.7

On reaction with aqueous hydrogen chloride, it yielded thedihydrochloride which melted at 265270 C. after recrystallization fromethanol-ether.

EXAMPLE 4 This illustrates the preparation and evaluation of a polyamidefrom 1,1,6,6-tetramethylhexamethylenediamine, namely,polytetramethylhexamethylenediamine sebacamide,

A charge consisting of 19.83 .parts of1,1,6,6-tetramethylhexamethylenediamine, 44.49 parts of diphenyldi-'thiolsebacate, and 16 parts of'purified p-xylene was placed in a glasstube. The tube was swept with oxygen-free nitrogen, evacuated, andsealed. The charge, sealed tube was heated from 150 C. 'to 210 C. in 30minutes and held at 210 C. for 'an hour. It was then opened and heatedfor 30 minutes at 255 C. under one atmosphere pressure. The pressure wasthereafter reduced to 3-4 mm. and the heating at 255 C. continued for anaddi- There was obtained 35 parts of a polymer having an inherentviscosity of 1.28 and which was clear and tough. Residual thiophenol wasremoved from the polymer by dissolving it in 550 parts of boilingdimethylformamide and precipitating by pouring the dimethylformamidesolution into a large volume of concentrated aqueous ammonia. Afterwashing with water and drying at C., the polymer had an inherentviscosity of 1.31. A film of the purified polymer was still tough after200 hours exposure to ultraviolet light and the polymer had an inherentviscosity of 1.28.

In contrast to the above, a film from a polyhexa methyleneadipamidehaving an inherent viscosity 0.85, exposed at the same time, was brittleafter 200 hours and the inherent viscosity was 0.72.

EXAMPLE This demonstrates the superior light stability of yarns preparedfrom a hexamethylenediamine in which the alpha carbon atoms werecompletely substituted as compared with yarns derived from homologousdiamines in which the alpha carbons were partially substituted andunsubstituted. The diamines and dicarboxylic acids from which theseyarns, designated as I, II and III, were derived is indicated below:

EFFECT OF U. V. LIGHT ON POLYAMIDE YARNS Tensile strength in grams p erdenier/elongation in percent Hours exposure Yarn I Yarn II Yarn III Itwill be noted that the behaviour of Yarn II also demonstrates thatsubstitution of the alpha carbon atoms in the dibasic acid from which apolymer is derived has little or no effect on light stability.

Having described my invention, I claim:

1. A 1,6-diamino-2,4-hexadiyne containing two primary amino groups andin which each carbon atom vicinal to each nitrogen atom is completelysubstituted by aliphatic radicals selected from the group consisting ofmethyl, ethyl, n-propyl, tetramethylene and pentamethylene groups.

2. 1,6-diamino-1,1,6,6-tetramethyl-2,4-hexadiyne.

3. The method of preparing in high yield a 1,6-diamino-2,4-hexadiyneinwhich the carbon atoms vicinal to the nitrogen atoms are completelysubstituted by aliphatic radicals which comprises coupling a primarypropargylamine in which the carbon atom vicinal to the nitrogen atom iscompletely substituted by aliphatic radicals selected from the groupconsisting of methyl, ethyl, n-propyl, tetramethylene and pentamethyleneby reaction with oxygen in the presence of a cuprous catalyst.

4. The method of preparing 1,6-diamino-1,1,6,6-tetramethyl-2,4-hexadiynein high yield by reacting 1,1-dimethyl propargylamine with oxygen in thepresence of a cuprous catalyst.

References Cited in the file of this patent FOREIGN PATENTS 619,206Great Britain Mar. 4, 1949 UNITED STATES PATENT OFFICE Certificate ofCorrection Patent No. 2,867,662 January 6, 1959 Thomas E. Londergan Itis hereby certified that error appears in the printed specification ofthe above numbered patent requiring correction and that the said LettersPatent should read as corrected below.

Column 3, line 30, for that portion of the equation readin NN read- --NHlines 34; and 35, for that portion of the equation re ing 5 read he.

line 54, for 50-62.6 C. read 50-52.6 G.--; column 6, line 8, for polymerread po1yamide.

Signed and sealed this 28th day of April 1959.

Attest= T. B. MORROW, ROBERT C. WATSON, Attestz'ng Ofiaer.Oom/miasz'onar of Patents.

1. A 1,6-DIAMINO-2,4-HEXADIYNE CONTAINING TWO PRIMARY AMINO GROUPS ANDIN WHICH EACH CARBON ATOM VICINAL TO EACH NITROGEN ATOM IS COMPLETELYSUBSTITUTED BY ALIPHATIC RADICALS SELECTED FROM THE GROUP CONSISTING OFMETHYL, ETHYL, N-PROPYL, TETRAMETHYLENE AND PENTAMETHYLENE GROUPS.